A currently available renewable energy conversion generator is a charger connected to a public power supply and controlled by a timer to charge more than one battery. The power stored in the battery is supplied to a direct-current (DC) motor via control of a motor controller, so that the DC motor operates to drive an alternating-current (AC) generator. The power generated by the AC generator is distributed to loads via a power distribution panel. Taking a wind energy power generation system as an example, there is included an AC generator, the power generated by which belongs to cell instead of battery and could not be used as normal electric power. Further, taking the solar energy power generation system as an example, the power generated by which belongs to cell instead of battery and could not be used as normal electric power, either. The power generation efficiency of these systems is always a problem. To overcome this problem, there are two solutions, one of which is to store the generated power in a battery for use as a backup power, and the other one of which is to directly use the generated power to drive a DC motor to reach a predetermined high rotational speed, so that the inertia acceleration of a counterweight flywheel rotating at high speed causes the DC motor to effortlessly and stably drive a permanent-magnet generator to operate and generate power (this type of generator is usually referred to as a flywheel generator or FWG). Therefore, the power generated from renewable energy can be stored as backup power during the off-peak hours, and the stored power is high-efficiently converted into the power supply required by loads during the on-peak hours.
Generally speaking, the currently available backup power conversion and output unit is mainly characterized in that the backup power stored in the battery is controlled by the motor controller for outputting to the DC motor for the same to operate, and then, the large torque of the inertia in motion of the counterweight flywheel mounted on the output shaft of the DC motor is utilized to drive the permanent-magnet generator to generate electric power, which is then distributed via a power distribution panel to AC loads as the power supply thereof. Basically, in the whole backup power conversion process of the conventional power conversion and output unit, some of the power is consumed to maintain constant operation of the motor, and the backup power is not really converted and utilized in the most power-saving or the most efficient manner. In other words, the power stored in the battery can only be used as backup power instead of the normal power supply. Further, the conditional factor for nonlinear control comes from the operation of the generator for generating power for use by loads. The higher the power generation is, the higher the load capacity of the motor will be; and the lower the power generation is, the lower the load capacity of the motor will be. Under this condition, when the generator works in the nonlinear operation mode, the generated electric energy is very unstable, the frequent change in the potential at the loads would inevitably result in abnormal or overlarge surge in the power output circuit to adversely affect the stability of power output. In the event this type of surge is not buffered or eliminated, the generator tends to be subject to instantaneous overload and become burned out. Apparently, for the conventional backup power conversion and output unit to extend the best energy-saving effect, it is necessary to solve the problem of anti-electromotive force or eddy current that is produced when the motor is nonlinearly controlled, and to buffer or eliminate the abnormal or overlarge surge in the nonlinear generator. Otherwise, the backup power conversion and output unit will only be a power conversion unit or even an energy-consuming unit.